Red light implants for treating osteoporosis

ABSTRACT

A method of irradiating spinal tissue with red light, comprising: inserting a cannulated device defining a bore into the spinal column, wherein the bore contains an optically transparent substrate adapted to emit red light, and transmitting red light through the substrate to intermittently irradiate tissue within the spinal column.

CONTINUING DATA

This application claims priority and is a continuation from co-pendingpatent application U.S. Ser. No. 15/286,857 “Red Light Implants forTreating Osteoporosis”, filed Oct. 6, 2016 (Attawia) (DEP5578USCNT4),which is a continuation from U.S. Ser. No. 15/175,353, entitled “RedLight Implants for Treating Osteoporosis”, filed Jun. 7, 2016 (Attawia)(DEP5578USCNT3), which is a continuation from U.S. Ser. No. 14/499,520,entitled “Red Light Implants for Treating Osteoporosis”, filed Sep. 29,2014 (Attawia) (now U.S. Pat. No. 9,474,912) (Docket No. DEP5578USCNT2),which is a continuation from U.S. Ser. No. 13/587,542, filed Aug. 16,2012, entitled “Red Light Implants for Treating Osteoporosis”, (Attawia)(now U.S. Pat. No. 8,845,703), (Docket No. DEP5578USCNT1), which is acontinuation from U.S. Ser. No. 11/235,674, filed Sep. 26, 2005,entitled Red Light Implants for Treating Osteoporosis”, (Attawia),(Docket No. DEP5578USNP) (now U.S. Pat. No. 8,262,713, thespecifications of which are incorporated by reference in theirentireties.

BACKGROUND OF THE INVENTION

Osteoporosis is a disease that results in the weakening of bone and anincrease in the risk of fracture. It has been reported that Americanfemales over the age of 50 have about a 50% chance of breaking a boneduring their lifetime, and a 40% chance of breaking either a hip,vertebra or wrist. Post-menopausal women lose about 1-3% of their bonemass for each of the first 5-7 years after menopause. Osteoporosis isbelieved to contribute to about 1.5 million fractures a year in theUnited States, including about 700,000 spinal fractures and about300,000 hip fractures. According to the Mayo Clinic, about 25% of thepeople over 50 who fracture a hip die within a year of the incident. Therisk of breaking a bone for an osteoporotic individual doubles after thefirst fracture. The risk of breaking a second vertebra for anosteoporotic individual increases about four-fold after the first spinalfracture.

Human bone comprises hard mineralized tissue and softer collagenoustissue. The combination of these tissues provides bone with both astructural, weight-bearing capability and a shock-absorption capability.As the bone ages, however, the collagenous portion of the bone is slowlymineralized, thereby making the entire bone more brittle. To compensatefor this, bone constantly undergoes a process called “remodeling” inwhich older, more mineralized bone is replaced by new, more collagenousbone.

Bone remodeling is undertaken by two competing processes: bone formationand bone resorption. Bone formation is largely achieved by bone-formingcells called osteoblasts, while bone resorption is largely achieved bybone-eating (bone-resorbing) cells called osteoclasts. In the normaldesired situation, the rate of bone formation is essentially equal tothe rate of bone resorption, so that bone mass in the body ismaintained.

Osteoporosis occurs when the rate of bone resorption exceeds the rate ofbone formation. The rate of bone resorption is largely dependent uponthe local production of osteoclasts.

Current treatments for osteoporosis have focused upon arresting theactivity of the osteoclast cells. In particular, osteoporosis therapyhas focused upon administering drugs called “anti-resorptive agents” orARA's. The most common classes of anti-resorptive drugs includeestrogen, selective estrogen receptor modulators (SERMs),biphosphonates, calcitonin, osteoprotegrin (OPG), cathespin K andstatins. Current products include FOSAMAX® (alendronate) in the U.S.,Biphosphonate DIDRONEL® (etidronate), and ACTONEL® (risedronate).

Despite the promise provided by these anti-resorptives, there stillremain serious issues. First, many anti-resorptives act in a manner thatwholly eliminates osteoclast activity. Thus, the delicate balancebetween bone formation and bone-resorption is again upset, and older,highly mineralized tissue remains within the bone. Although this has theeffect of increasing bone mineral density (BMD), the bone that remainsis fragile and prone to microdamage.

Second, many of the anti-resorptives are administered systemically,through either oral or intravenous means. Accordingly, side effectsassociated with systemic administration are often seen. For example, thesystemic administration of hormone replacement therapy (“HRT”) has beenassociated with an elevated cancer risk. In response to this concern,some anti-resorptive drugs, such as biphosphonates, have been engineeredto be selective for bone tissue. However, in many cases, the amount ofsuch tissue selective drug that actually reaches bone is often less than100%.

With respect to the spine, one of the manifestations of osteoporosis isthe low pullout strength of pedicle screws. Simply, the lower density ofthe cancellous bone in the vertebral body reduces the amount of purchaseavailable to a pedicle screw implant.

The art has described a number of different methods for enhancing thepull out strength of pedicle screws. These methods include the use ofexpandable screws (Cook, Spine Journal, 1 (2001) 109-114 and Cook, SpineJournal, 4 (2004) 402-8), and of injectable, settable fluids around thepedicle screw (Bai, Spine, 26(24) 2679-83).

SUMMARY OF THE INVENTION

The present inventors have developed methods and devices for enhancingthe integration of pedicle screws into vertebrae. In particular, thepresent inventors have developed inventions using red light irradiationof the bone-pedicle screw interface to enhance the integration of thepedicle screw into the vertebra.

The literature reports that red light irradiation enhances the pull-outstrength of dental implants. For example, Khandra, Clin. Oral ImplantsRes., 2004, June:15(3):325-332, reports that in vivo red lightirradiation of dental implants increased the pullout strength of theseimplants by about 40%. See also, Khandra, Swed. Dent. J. Suppl., 2005,(172) 1-63. Guzzardella, Int. J. Artif. Organs, 2001, December 24(12):898-902 reports that red light irradiation of HA nails drilled intorabbit femurs resulted in a higher degree of HA-bone integration, andconcluded that low power laser treatment can be considered a good toolto enhance the bone-implant interface in orthopedic surgery.

The literature has further reported on possible reasons why red lightirradiation of implants results in enhanced osteointergration. Khandra,Clin Oral Implants Res. 2005, April 16(2) 168-75 reports that red lightirradiation of human fibroblasts cultured upon titanium implant materialproduces results in a significantly higher incidence of cell attachment.Lopes, Photomed. Laser Surg. 2005 Feb. 23(1) 27-31 reports that redlight irradiation of dental implants implanted into rabbit femursresulted in a significant increase in calcium HA concentration.Dortbudak, Clin. Oral Implants Res., 2002, June 13(3) 288-92, reportsthat red light irradation of wounded bone resulted in a nearly 20%increase in viable osteocyte count, while not affecting bone resorptionrate.

Therefore, in accordance with the present invention, there is providedmethod of treating a vertebra, comprising the steps of:

a) implanting an implant into a cancellous bone region of the vertebra,and

b) irradiating the cancellous bone region with an effective amount ofred light.

DESCRIPTION OF THE FIGURES

FIG. 1 discloses a glass screw embodiment of the present invention.

FIG. 2 discloses a cannulated screw with glass cylinder.

FIG. 3A discloses a cap-screw assembly, wherein the cap transmits lightthrough the screw.

FIGS. 3B-3C each disclose a cap for a screw, wherein the cap transmitslight through the screw.

FIG. 4 discloses a cap for a screw, wherein the cap transmits lightdirectly into bone.

FIG. 5 discloses a collar for a screw, wherein the collar transmitslight through the screw.

FIG. 6 discloses a helical embodiment of the present invention.

FIG. 7 discloses a helical embodiment of the present invention adaptedto irradiate a pedicle screw augmented with cement.

FIG. 8 discloses an exemplary implant powered by an external lightsource.

FIG. 9 discloses a red light implant of the present invention powered byan external Rf antenna.

FIG. 10 discloses a red light implant of the present invention poweredby an internal power source.

FIG. 11 discloses exemplary circuit that may accommodate an LEDcomponent of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In some embodiments, the red light is delivered to the implant-boneinterface through the pedicle screw. In these situations, it ispreferred that the pedicle screw be made of a material capable oftransmitting red light, such a single crystal alumina. Now referring toFIG. 1, there is provided a red light implant 1, comprising:

-   -   a) a pedicle screw 3 made of a red light transmitting material        and having:        -   i) a distal tip 5,        -   ii) an intermediate shaft 7 having a distal threaded portion            9 and a proximal smooth portion 11, and        -   iii) a proximal end portion 13 adapted for receiving a rod            or other static or dynamic fixation device (e.g., a plate or            a tether),    -   b) a red light LED 15 abutting the proximal portion of the        screw,    -   c) an Rf antenna 17 for receiving Rf energy positioned upon the        proximal smooth portion of the and electrically connected to the        red light LED, and    -   d) a red light reflective coating 19 the proximal end portion        and the proximal smooth portion of the screw.        The red light reflective coating (such as a metal) directs red        light emitted by the LED distally towards the threaded portion        of the screw.

In use, the screw is implanted and Rf energy is directed towards the Rfantenna portion of the implant. The Rf energy activates the LED whichthen emits red light, which travels throughout the screw. The red lightexits the screw and irradiates the adjacent cancellous bone, therebystimulating bone repair and osteointegration of the implant. Althoughthe illustrated pedicle screw 3 is a monoaxial pedicle screw, thepedicle screw of the present invention can be any type of pedicle screw,including for example, a polyaxial pedicle screw.

In other embodiments wherein the red light is delivered through thescrew, the red light is delivered through a cannulated pedicle screw.Now referring to FIG. 2, there is provided a red light implant 21,comprising:

-   -   a) a pedicle screw 23 made of a metallic material and having:        -   i. a distal tip 25,        -   ii. an intermediate shaft 27 having an outer surface 28            having a distal threaded portion 29, a proximal smooth            portion 31 and throughholes 32,        -   iii. a proximal end portion 33 adapted for receiving a rod            or other static or dynamic fixation device,        -   iv. a longitudinal bore 36 communicating with the            throughholes,    -   b) a red light LED 35 abutting the proximal portion of the        screw,    -   c) an Rf antenna 37 for receiving Rf energy positioned upon the        proximal smooth portion of the and electrically connected to the        red light LED, and    -   d) a rod 39 comprising a red light transmitting material and        disposed within the longitudinal bore.

Within the bore, the rod of red light transmitting material may beinserted so that red light can be shined upon the proximal end portionof the screw and delivered through the red light transmitting rod andthroughholes to the cancellous regions surrounding the screw.

In some embodiments, a conventional pedicle screw is implanted and thered light is delivered via a second implant that preferably surroundsthe pedicle screw

In some embodiments, the second implant is a cap that rests against theproximal end of the pedicle screw.

In some embodiments, the cap transmits light through the screw. Nowreferring to FIG. 3a , there is provided a there is provided a red lightimplant 41, comprising:

-   -   a) a pedicle screw 43 made of a red light transmitting material        and having:        -   i. a distal tip 45,        -   ii. an intermediate shaft 47 having an outer surface 48            having a distal threaded portion 49 and a proximal smooth            portion 51,        -   iii. a proximal end portion 53 adapted for receiving a rod            or other static or dynamic fixation device and having a            threaded outer surface 54, and    -   b) a cap 55 having a threaded inner surface 56 adapted to engage        the threaded outer surface of the proximal end portion of the        screw and made of a red light transmitting material.

In use, the cap transmits light from itself to the screw via thethreaded surface interface.

In some embodiments, and now referring to FIG. 3b , the cap is adaptedto transmit red light that has been transdermally applied. Such a capcomprises a light reflective coating 57 upon the various surfaces of thecap, but has an uncoated proximal end portion that accepts thetransdermally delivered light.

In some embodiments, and now referring to FIG. 3c , the cap contains ared light light emitting diode (LED) 58 and a power source 59 (such anantenna or battery).

Now referring to FIG. 4, there is provided a there is provided a redlight implant 61, comprising:

-   -   a) a pedicle screw 63 made of a metallic material and having:        -   i. a distal tip 65,        -   ii. an intermediate shaft 67 having an outer surface 68            having a distal threaded portion 69 and a proximal smooth            portion 71,        -   iv. a proximal end portion 73 adapted for receiving a rod,            and    -   b) a cap 75 adapted to fit around the proximal end portion of        the screw and made of a red light transmitting material, the cap        comprising:        -   i. an uncoated distal end portion 77,        -   ii. an intermediate portion 79 coated with a light            reflective material 81, and        -   iii. an uncoated proximal end portion 83.

In some embodiments, the second implant is a collar that sits distal tothe head of the screw. The collar contains a red light LED and a powersource. Now referring to FIG. 5, there is provided a red light implant101, comprising:

-   -   a) a pedicle screw 103 made of a red light transmitting material        and having:        -   i) a distal tip 105,        -   ii) an intermediate shaft 107 having a distal threaded            portion 109 and a proximal smooth portion 111, and        -   iii) a proximal end portion 113 adapted for receiving a rod,    -   b) a red light LED 115 surrounding the proximal smooth portion        of the shaft,    -   c) an Rf antenna 117 for receiving Rf energy positioned upon the        proximal smooth portion and proximal to the LED, and    -   d) a red light reflective layer coating 119 covering the LED.

In some embodiments, it is preferred that the second implant has ahelical shape and is implanted around the pedicle screw. The helicalshape is preferred because it can be delivered in a minimally invasivemanner, and can irradiate essentially the entire surface area of thepedicle screw.

Now referring to FIG. 6, there is provided an implant 121 for deliveringred light to an implant-vertebra interface, comprising:

-   -   a) a helix 123 comprising a red light transmitting material and        having a proximal end portion 125 and a distal end portion 127,        and    -   b) a red light source 131 connected to the proximal end portion        of the helix and comprising i) a red light LED 135 and ii) a        power source 137 electrically connected to the red light LED.

Still referring to FIG. 6, the helical implant is implanted in avertebral body along with a pedicle screw 139. As shown, the helix isco-axial with the pedicle screw. The helical nature of the implantallows red light irradiation of the full diameter of the screw along itslongitudinal axis.

In some embodiments, the red light implant may be a double helix inorder to provide a more even illumination of the cancellous bone.

In some embodiments, the red light treatment of the present inventioncan be used in conjunction with the injection of a settable paste aroundthe pedicle screw. It is believed that the red light will enhance theosteointegration of the paste to the surrounding bone.

Preferably, the settable paste comprises calcium phosphate (CaP) orhydroxyapatite (HA). As noted above, Guzzardella, Int. J. Artif. Organs,2001, December 24(12): 898-902 reported that red light irradiation of HAnails drilled into rabbit femurs resulted in a higher degree of HA-boneintegration, and concluded that low power laser treatment can beconsidered a good tool to enhance the bone-implant interface inorthopedic surgery.

Therefore, in accordance with the present invention, there is provided amethod of treating a vertebra, comprising the steps of:

a) implanting an implant into the vertebra,

b) injecting a paste around the implant, and

c) irradiating the paste with an effective amount of red light.

In preferred embodiments, and now referring to FIG. 7, the pedicle screw139 is cannulated and comprises holes 141 and the injectable, settablepaste 143 is injected through the cannula of the screw and thenirradiated with red light delivered from the helix 123.

Therefore, in preferred embodiments of the present invention, there isprovided a method of treating a vertebra, comprising the steps of:

-   -   a) implanting a pedicle screw having an outer surface, a central        bore, and a plurality of throughholes extending between the        outer surface and the central bore,    -   b) injecting a settable paste into the bore so that the paste        extrudes through the throughholes, and    -   c) irradiating the extruded paste with an effective amount of        red light.

In some embodiments, the power source can be a battery.

In other embodiments, the power source can be an Rf antenna adapted toreceive Rf energy for an external Rf antenna.

In order to protect the active elements of the device from the CSF, insome embodiments, the red light LED is encased in a casing. This casingboth protects the LED components from body fluids, and also prevents theLED components from eliciting a violent immune reaction In someembodiments, the casing is made of a red light transparent material. Thered light transparent material may be placed adjacent the LED componentso that red light may be easily transmitted therethrough. In someembodiments, the red light transparent casing is selected from the groupconsisting of silica, alumina and sapphire. In some embodiments, thelight transmissible material is selected from the group consisting of aceramic and a polymer. Suitable red light-transmissible ceramics includealumina, silica, CaF, titania and single crystal-sapphire. Suitable redlight transmissible polymers are preferably selected from the groupconsisting of polypropylene and polyesters.

In some embodiments, the red light-transmissible implant comprises a redlight transmissible polymer. In other embodiments, the redlight-transmissible implant comprises a UVB-transmissible ceramic, suchas glass. The glass content of the implant is preferably in the range of20-40 volume percent (“v/o”). At higher glass glass contents, theimplant becomes relatively inelastic. At lower implants, red lighttransmission is more problematic. The red light transmissible componentof the implant may be in the form of beads, long fibers or choppedfibers.

In some embodiments, energy (such as Rf energy or red light) isdelivered transdermally and collected near the skin layer of thepatient. Such a configuration would allow light to be delivered deepwithin the patient, or in or near critical organs or tissues, and yethave the light source and associated components in a less sensitiveregion. This configuration allows easier access to the light/controllershould the need arise for service or maintenance, and also allow formore efficient transdermal energy transmission. Moreover, by using ahollow tube with reflective internal surfaces, light and therapeuticfluids could be delivered to the implanted device. The lightsource/controller implanted near the patient's skin could also be asimple, hollow chamber made to facilitate the percutaneous accessdescribed above. The advantages and benefits of this system include:

-   -   a) further removal from the deep site of the functional implant,        thereby reducing risk of contamination of the deeper site by        percutaneous access;    -   b) easier precutaneous access by being closer to the skin        surface and having a larger surface area or target to access        with the needle;    -   c) a larger volume could hold more therapeutic fluid to provide        a longer duration of activity; and    -   d) a central reservoir could provide therapy to multiple        implants throughout the body.

In use, the surgeon implants the implant into the spine of the patientso that the Rf receiving antenna is adjacent the posterior portion ofthe vertebral body.

In some embodiments wherein the red light is delivered transdermally, itmay be advantageous to provide the red light collection closer to theskin. Now referring to FIG. 8, there is provided a first exemplaryimplant having an external light source. The externally based-controldevice has a light source 101 for generating light within the device.The light generated by this source is transmitted through fiber opticcable 103 through the patient's skin to an internally-based light port109. The light port is adapted to be in light-communication with fiberoptic cable 221 disposed upon the proximal surface 203 of the helicalimplant 201. The helix receives the light and transmits the light to theadjacent cancellous tissue.

Now referring to FIG. 9, there is provided a second exemplary unithaving an internal light source. Externally based-control device 222 hasan RF energy source 224 and an antenna 230 for transmitting signals toan internally-based antenna 232 provided on the prosthesis. Theseantennae 230, 232 may be electro-magnetically coupled to each other. Theinternal antenna 232 sends electrical power to a light emitting diode(LED) 234 disposed internally on the implant in response to thetransmitted signal transmitted by the external antenna 230. The lightgenerated by the LED travels across the red light transparent-singlecrystal alumina implant 238 and into the cancellous tissue.

In some embodiments, and now referring to FIG. 10, the prosthesis havingan internal light source further contains an internal power source 300,such as a battery (which could be re-chargeable), which is controlled byan internal receiver and has sufficient energy stored therein to deliverelectrical power to the light source 234 in an amount sufficient tocause the desired light output.

When the implant is coupled with external energy, power can betransmitted into the internal device to re-charge the battery.

In some embodiments, the light generated by the implant is powered bywireless telemetry integrated onto or into the implant itself. In theFIG. 9 embodiment, the LED 234 may comprise a radiofrequency-to-DCconverter and modulator. When radiofrequency signals are emitted by theexternal antenna 230 and picked up by the internal antenna 232, thesesignals are then converted by the receiver (not shown) into electricalcurrent to activate the light source of the PCO unit.

In one embodiment, the implant may have an internal processor adapted tointermittently activate the LED.

In some embodiments, the telemetry portion of the device is provided byconventional, commercially-available components. For example, theexternally-based power control device can be any conventionaltransmitter, preferably capable of transmitting at least about 40milliwatts of energy to the internally-based antenna. Examples of suchcommercially available transmitters include those available fromMicrostrain, Inc. Burlington, Vt. Likewise, the internally-based powerantenna can be any conventional antenna capable of producing at leastabout 40 milliwatts of energy in response to coupling with theexternally-generated Rf signal. Examples of such commercially availableantennae include those used in the Microstrain Strainlink™ device.Conventional transmitter-receiver telemetry is capable of transmittingup to about 500 milliwatts of energy to the internally-based antenna.

In some embodiments, and now referring to FIG. 11, the implant includesa light emitting diode (LED) 234 built upon a portion 307 of theimplant, along with the required components to achieve trans-dermalactivation and powering of the device. These components can include, butare not limited to, RF coils 301, control circuitry 303, a battery 305,and a capacitor. Such a device could be capable of intermittent orsustained activation without penetrating the skin, thereby avoidingtrauma to the patient and/or risk of infection from skin-borne bacteria.As shown above, the accessory items needed to power and control the LEDmay be embedded within the implant. However, they could also be locatedon the surface(s) of the implant, or at a site adjacent to or near theimplant, and in communication with the implant.

To enhance the propagation of light emitted from the end of the device,a lens could be placed at the distal end of the device to spread thelight, or a diffuser such as a small sheet or plate of optical materialcould be used to create more surface area. Alternatively, one couldcreate a series of lateral diffusers, such as grooves or ridges, alongthe distal portion of end of the device to spread light out from 360degrees perpendicular to the axis of the device, as well as emanatingdirectly out from the end of the fiber.

Preferably, the red light of the present invention has a wavelength ofbetween about 600 nm and about 1000 nm. In some embodiments, thewavelength of light is between 800 and 900 nm, more preferably between800 nm and 835 nm. In some embodiments, the wavelength of light isbetween 600 nm and 700 nm.

In some embodiments, the light source is situated to irradiate adjacenttissue with between about 0.02 J/cm² and 200 J/cm² energy. In someembodiments, the light source is situated to irradiate adjacent tissuewith between about 0.2 J/cm² and 50 J/cm² energy, more preferablybetween about 1 J/cm² and 10 J/cm² energy. In some embodiments, thelight source is situated to produce an energy intensity of between 0.1watts/cm² and 10 watts/cm². In some embodiments, the light source issituated to produce about 1 milliwatt/cm².

In some embodiments, the light source emits lights consistingessentially of red light having a wavelength between 600 nm and 1000 nm.In others, the light source emits a wide spectrum of light and includesthe emission of red light having a wavelength between 600 nm and 1000 nmwith a strength of between about 0.02 J/cm² and 200 J/cm² energy. In oneof these wide spectrum embodiments, white light is used as the lightsource. In some embodiments thereof, the device includes a filter thatfilters out at least some of the wavelengths outside of the 600-1000 nmrange.

Therefore, in some embodiments of the present invention, the therapeuticdose of red light is provided on approximately a daily basis, preferablyno more than 3 times a day, more preferably no more than twice a day,more preferably once a day.

In some embodiments of the present invention, the implant comprises anintervertebral motion disc and a red light source adapted to enhance theosteointegration of the endplates of the motion disc to the adjacentvertebrae.

We claim:
 1. A method of irradiating spinal tissue with red light,comprising: a) inserting a system into the spinal column, wherein thesystem comprises a red light source and contains an opticallytransparent substrate adapted to emit red light, b) transmitting redlight through the substrate to irradiate tissue within the spinalcolumn, wherein the system further contains a receiver adapted toreceive electromagnetic energy and convert the electromagnetic energyinto an electrical current to activate a light source and wherein thesystem further comprises an internal processor adapted to intermittentlyactivate the red light source.